Lecture 4 - Method of Sections -
Trusses
Type Lecture
Date @September 28, 2023
Materials https://www.youtube.com/watch?v=Yt4XvWFdei0&t=1s
Reviewed
Trusses/Frames - Axial
Beams/Bending Elements - Shear, Bending Moment
Some FBD Symbols
Method of Sections
MoS for solving trusses
MoS for solving beams
Force Diagrams
Typical Force Diagrams
Bonus Examples
Last Week:
We want things to stay still
If there are still they are in equilibrium
If they are in equilibrium they aren’t moving in any of the 6 degrees of freedom
We often break the problem into a 2D problem, with 3 degrees of freedom
Which means we want ΣFx = 0 and ΣFy = 0 and ΣMz = 0
Lecture 4 - Method of Sections - Trusses 1
, We can use these equations to solve for the Reactions of the system that keep it in
Static Equilibrium
But what happens INSIDE the elements?
FBD - Implied (Partial) FBD)
Implied at Joint - or what is happening at
the dot
If an arrow is pointing toward the joint
it means it is in compression
If an arrow is pointing away it is in
tension
Implied in Members - or what is
happening at the dot
Truss 01 - FBD
Solve for the reactions
Lecture 4 - Method of Sections - Trusses 2
Trusses
Type Lecture
Date @September 28, 2023
Materials https://www.youtube.com/watch?v=Yt4XvWFdei0&t=1s
Reviewed
Trusses/Frames - Axial
Beams/Bending Elements - Shear, Bending Moment
Some FBD Symbols
Method of Sections
MoS for solving trusses
MoS for solving beams
Force Diagrams
Typical Force Diagrams
Bonus Examples
Last Week:
We want things to stay still
If there are still they are in equilibrium
If they are in equilibrium they aren’t moving in any of the 6 degrees of freedom
We often break the problem into a 2D problem, with 3 degrees of freedom
Which means we want ΣFx = 0 and ΣFy = 0 and ΣMz = 0
Lecture 4 - Method of Sections - Trusses 1
, We can use these equations to solve for the Reactions of the system that keep it in
Static Equilibrium
But what happens INSIDE the elements?
FBD - Implied (Partial) FBD)
Implied at Joint - or what is happening at
the dot
If an arrow is pointing toward the joint
it means it is in compression
If an arrow is pointing away it is in
tension
Implied in Members - or what is
happening at the dot
Truss 01 - FBD
Solve for the reactions
Lecture 4 - Method of Sections - Trusses 2
